[Blink, RemotePlayback] Dismissing the dialog rejects with NotAllowedError.

third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef RemotePlayback_h
 #define RemotePlayback_h
 
 #include "bindings/core/v8/ActiveScriptWrappable.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "core/events/EventTarget.h"
+#include "modules/ModulesExport.h"
 #include "platform/heap/Handle.h"
 #include "public/platform/modules/remoteplayback/WebRemotePlaybackClient.h"
 #include "public/platform/modules/remoteplayback/WebRemotePlaybackState.h"
+#include "wtf/Compiler.h"
 #include "wtf/text/AtomicString.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class ExecutionContext;
 class HTMLMediaElement;
 class LocalFrame;
 class RemotePlaybackAvailability;
 class ScriptPromiseResolver;
 
-class RemotePlayback final : public EventTargetWithInlineData,
-                             public ActiveScriptWrappable,
-                             private WebRemotePlaybackClient {
+class MODULES_EXPORT RemotePlayback final
+    : public EventTargetWithInlineData,
+      public ActiveScriptWrappable,
+      WTF_NON_EXPORTED_BASE(private WebRemotePlaybackClient) {
   DEFINE_WRAPPERTYPEINFO();
   USING_GARBAGE_COLLECTED_MIXIN(RemotePlayback);
 
  public:
   static RemotePlayback* create(HTMLMediaElement&);
 
   // EventTarget implementation.
   const WTF::AtomicString& interfaceName() const override;
   ExecutionContext* getExecutionContext() const override;
 
   ScriptPromise getAvailability(ScriptState*);
   ScriptPromise prompt(ScriptState*);
 
   String state() const;
 
   // ScriptWrappable implementation.
   bool hasPendingActivity() const final;
 
   DEFINE_ATTRIBUTE_EVENT_LISTENER(statechange);
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
+  friend class RemotePlaybackTest;
+
   explicit RemotePlayback(HTMLMediaElement&);
 
   // WebRemotePlaybackClient implementation.
   void stateChanged(WebRemotePlaybackState) override;
   void availabilityChanged(bool available) override;
   void promptCancelled() override;
 
   WebRemotePlaybackState m_state;
   bool m_availability;
   HeapVector<Member<RemotePlaybackAvailability>> m_availabilityObjects;
   Member<HTMLMediaElement> m_mediaElement;
   Member<ScriptPromiseResolver> m_promptPromiseResolver;
 };
 
 }  // namespace blink
 
 #endif  // RemotePlayback_h